Videoconferencing uses telecommunications of audio and video to bring people at different sites together for a meeting. This can be as simple as a conversation between two people in private offices (point-to-point) or involve several sites (multipoint) with more than one person in a number of rooms at different sites. Besides the audio and visual transmission of people, videoconferencing can be used to share documents, computer-displayed information, and whiteboards.
Videoconferencing among multiple remote points is sometimes facilitated employing Multipoint Control Unit (MCU). An MCU is a bridge that interconnects calls from several sources. All parties call the MCU, or the MCU may call the parties which are going to participate, for initiating the conference. MCUs may use various protocols such as Internet Protocol (IP), and be structured as software program(s), hardware, or combination of the two. One of the main tasks for an MCU is to organize the conference based on capabilities of the participating parties (e.g. receiving parties and source in a single source directed conference).
MCU controlled video conferences may be facilitated supporting a fixed resolution video stream or accommodating multiple video streams with different resolutions. The conference may be initiated directly by the MCU or escalate from a peer-to-peer chat, where each participant may be provided the ability to request and deliver multiple video sources. When multiple participants with different capabilities request varying resolutions, it is a challenge for the MCU to coordinate those and accommodate the video conference in an optimized fashion, especially if the number of participants is large.